This invention relates to a coiled tubing injector assembly which comprises a gooseneck, which may also be referred to as a tubing guide, and a coiled tubing injector apparatus.
Reeled or coiled tubing has been run into completed wells for many years for performing certain downhole operations. Those operations include, but are not limited to, washing out sand bridges, circulating treating fluids, setting downhole tools, cleaning the internal walls of well pots, conducting producing fluids or lift gas, and a number of other similar remedial or production operations. The tubing utilized for such operations is generally inserted into the wellhead through a lubricator assembly or stuffing box. Typically, there is a pressure differential on the well so that the well is a closed chamber producing oil or gas or a mixture thereof from the pressurized well. The tubing that is inserted into the well is normally inserted through a lubricator mechanism which seals the well for pressure retention in the well.
The tubing is flexible and can bend around a radius of curvature and is normally supplied on a drum or reel. The tubing is pooled off the reel and inserted into a coiled tubing injector assembly. The coiled tubing injector assembly essentially comprises a curvilinear gooseneck, or tubing guide, and a coiled tubing injector apparatus positioned therebelow.
The curvilinear tubing guide forms an upper portion of the coiled injector assembly while the coiled tubing injector apparatus forms a lower portion thereof. Most coiled tubing injector apparatus utilize a pair of opposed drive chains arranged in a common plane. Such drive chains are made up of links, rollers, and gripper blocks. The drive chains are generally driven by sprockets powered by a motor which is a reversible hydraulic motor. The opposed drive chains grip the coiled tubing and are backed up by linear beams, also referred to as pressure beams, so that a number of pairs of opposed gripping blocks are in gripping engagement with the tubing at any given moment. Coiled tubing injector apparatus are shown in U.S. Pat. No. 6,209,634 to Avakov et al., U.S. Pat. No. 5,553,668 to council et al., U.S. Pat. No. 5,094,340 to Avakov, and U.S. Pat. No. 4,655,291 to Cox, all of which are incorporated herein by reference in their entirety. A tubing guide is shown in U.S. Pat. No. 5,799,731, the details of which are incorporated herein by reference in its entirety.
Typically, to insert the coiled tubing into the well, the coiled tubing is first spooled off of the reel and is placed on the tubing guide and inserted through a base of the tubing guide. The tubing guide will typically be placed on an installation platform such as a trailer when the tubing is installed therethrough. Once the coiled tubing is inserted through the base of the tubing guide, the coiled tubing must be manually clamped to the tubing guide. Typically, a clamp of a type known in the art is manually placed on the coiled tubing below the base of the tubing guide. Because the coiled tubing has been spooled from a reel, the residual stresses in the coiled tubing will try to pull the coiled tubing from the tubing guide. Once the coiled tubing is clamped, the tubing guide is lifted with a crane or other piece of equipment known in the art, and moved to the coiled tubing injector apparatus. If the coiled tubing is not clamped, the residual stresses in the coiled tubing will cause the coiled tubing to be released from the tubing guide, and the coiled tubing can whip in an uncontrolled fashion, which is extremely dangerous to personnel in the area. The tubing guide is placed over the coiled tubing injector apparatus and is lowered so that the length of coiled tubing extending through the base of the tubing guide can be engaged by the gripper chains in the coiled tubing injector apparatus. Once the coiled tubing is engaged by the gripper chains, the clamp must be manually removed by a worker who must reach between the base of the tubing guide and the coiled tubing injector apparatus prior to the time the tubing guide is placed directly on top of the coiled tubing injector apparatus. Once the clamp is removed, the tubing guide can be lowered completely so that it engages a coiled tubing injector frame of the coiled tubing injector apparatus.
The tubing guide has pins, referred to as base pins, extending downwardly from the tubing guide base. The base pins are received in legs of the coiled tubing injector frame. Once the tubing guide is placed in position on the frame, latch pins may be inserted through the legs of the injector frame into latch pin receptacles defined in the base pins, so that the tubing guide is latched or secured to the injector frame. The present manner of inserting a latch pin requires that a worker manually insert the latch pins which requires the worker to operate at or near the top of the injector frame. If it is desired to remove the latch pins, the latch pins must be manually removed.
Although the present manner of clamping the coiled tubing to the tubing guide and of latching the tubing guide to the injector frame works, there are inherent concerns with those methods. To remove the clamp, a worker must position his arm between the tubing guide and the injector frame which is being lowered onto the injector frame. The clamp is removed after a length of tubing has been engaged by the gripper chains. A clamp must also manually be placed on the tubing if it is desired to remove the tubing guide from the coiled tubing injector apparatus which also requires a worker to position his arm between the tubing guide and injector frame.
The latch pins must also be manually removed by an operator at or near the top of the coiled tubing injector frame. Thus, there is a need for an apparatus and method which will positively clamp coiled tubing to the tubing guide so that it will not be released from the tubing guide while the tubing guide is being moved from an installation platform to the coiled tubing injector frame or when it is removed from the coiled tubing injector frame. Likewise, there is a need for a method and apparatus which will allow the tubing guide to be latched to the coiled tubing injector frame and unlatched therefrom without the necessity of personnel manually installing and retracting latch pins at or near the top of the coiled tubing injector frame.